Common sources of disruption to airline schedules include crew absences, mechanical failure, inclement weather, etc. Disruption events can occur without any notification and with immediate effect such as when an airport closes due to a radar failure. Other disruption events, such as might occur because of deteriorating weather conditions, can have a more gradual effect on airline schedules. Planned airport or airspace closures cause disruption events with a defined time period where the defined time period can be static or can dynamically change during the disruption event.
In response to a disruption event, airlines reschedule their operations by implementing recovery plans for schedule, aircraft, crews and passengers that can include delaying or canceling flights, normally via an airlines operations control center (AOCC). Operators in an AOCC of a major airline manage the execution of hundreds or thousands of flights a day and adjust in real time the movements of the aircraft and crewmembers of the airline to minimize costly delays and cancellations, while complying with complex maintenance and routing constraints. These operators are responsible for preparing flight plans, adjusting the airline schedule including flight schedule, departure slot assignments, aircraft assignments and crew assignments in response to various disruption events. A challenge for major airlines is to limit inefficiency in the airline and manage information efficiently to alleviate the impact of unforeseen schedule disruptions.